-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KBTV 260233
AFDBTV

Area Forecast Discussion
National Weather Service Burlington VT
1033 PM EDT Wed Apr 25 2018

.SYNOPSIS...
Areas of low pressure will affect the area through the upcoming
weekend with near seasonable temperatures and a periodic threat
of showers. Fair and much warmer weather returns to the region
by the early to middle portions of next week as strong high
pressure builds across the eastern half of the nation.

&&

.NEAR TERM /THROUGH THURSDAY NIGHT/...
As of 1030 PM EDT Wednesday...Water vapor shows potent short
wave energy off the mid atlantic coast with deep moisture
advection across our cwa. This combined with approaching energy
from the west continues to produce areas of showers with
embedded heavier elements. Band of moderate rain lifting across
the central/northern cpv should be north of our cwa by early
Thursday morning...with a brief break before more showers
develop toward morning. Otherwise...temps are holding in the
upper 40s to lower 50s with the clouds/precip. No significant
changes to current forecast, just adjusted pops/qpf to show
higher values across the cpv and parts of northern ny.

Previous discussion below:
The forecast remain on track as we head into the evening hours.
Our first wave of light rain is now lifting into northern
counties while a distinct dry slot surges northward in advance
of a slowly approaching upper shortwave trough across the
eastern Great Lakes. Our area will largely lie within the dry
slot regime this evening into the first half of tonight, and as
such precipitation will trend more scattered and showery in
nature with areal pops lowering into the chance category -
especially for the eastern half of the forecast area. By later
tonight the aforementioned upper trough pivots into the area
with a general reblossoming of activity later tonight. Low
temperatures a blend of available guidance - mainly 40s.

The upper trough then swings through the area during the morning
hours on Thursday as bands of showers pivot east to west across the
area - especially north. The central core of this feature is fairly
compact with rather cool thermal profiles in the 700-500 mb level.
This, along with good PVA and moisture convergence on the front nose
of this feature warrants higher pops in the 60-80 percent range
through the morning hours, again most concentrated across northern
counties. By afternoon the main upper feature begins to exit east so
pops gradually wane toward evening. Highs to run quite similar to
today as winds trend light westerly over time - mainly 50s with a
few upper 40s across the Adirondacks.

A brief window of drier weather then arrives for Thursday night as
weak shortwave ridging evolves between the departing trough and
additional energy taking shape across the southeast. Given broad
consistency in this idea among this morning`s models a mainly rain-
free night is expected as skies trend partly cloudy over time. Low
temperatures a tad cooler in the upper 30s to lower 40s in
general.

&&

.SHORT TERM /FRIDAY THROUGH SATURDAY/...
As of 348 PM EDT Wednesday...Friday morning will start off dry
as shortwave ridging builds in, however some showery
precipitation will spread northward throughout the afternoon as
a surface low lifts out of the southeastern United States.
Models continue to struggle to come to a consensus on the track
of this low, with the GFS remaining steadfast in the furthest
west track, while the previous outlier ECMWF has come into
better line with the NAM/GEM track that takes the low up the
coast. By Friday afternoon however, models are coming to better
agreement that the aforementioned low will become absorbed into
the broader longwave trough, phasing to some extent with
northern stream energy rounding the trough from central Canada.
As multiple shortwaves gyrate within the base of the broader
longwave trough over the northeastern US, the North Country will
see an extended period of showery weather through Saturday. It
looks like the entire Friday through Saturday time period
certainly won`t be one big washout, but rather on and off
showery precipitation closely tied to individual shortwaves.
These features are notoriously difficult to time this far out,
so have stuck with chance PoPs for this time period, but expect
to have a better handle of timing/location of individual waves
within the next few forecast packages.

&&

.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
As of 348 PM EDT Wednesday...The generally unsettled weather will
continue Saturday night through Sunday night as the dynamic
upper-level trough remains over the Northeast. The trough will
also bring a shot of cooler air that will limit temperatures
Sunday from climbing above the upper 40s/low 50s. The cold air
advection will also support a well mixed boundary layer during
the day time hours, so Sunday afternoon will feel a little
breezy.

The pattern shifts Monday morning however as the trough pushes
east and expansive ridging pushes in from the west.
Southwesterly return flow around a building surface high to our
south will support a warming trend for the first half of the
work week. Everything is still on track for us to see temps in
the upper 50s/low 60s Monday, then into the low to mid 70s for
Tuesday and Wednesday.

&&

.AVIATION /03Z THURSDAY THROUGH MONDAY/...
Through 00z Friday...Extremely challenging aviation forecast
tonight with regards to ifr/lifr potential at our taf sites.
Current obs show very high sfc dwpts in the upper 40s to lower
50s with limited spread...while areas of moderate rain impact
kmss/kslk. Thinking a brief period of ifr vis in the rain is
possible thru 01z at both locations...with ifr/lifr cigs
prevailing at kmss. Based on available boundary layer moisture
and rain lifting north...combined with light sfc winds...would
not be surprised areas of br/fog develop at slk/mpv overnight.
Have mention tempo for 2sm in br. Also, some br with ifr vis is
possible at pbg. Otherwise...as wind shift to the southwest at
slk this evening, expect cigs to lower to ifr conditions and
continue into Thursday morning with developing ifr cigs likely
toward 06z at mpv/rut. Elsewhere at btv expecting mainly mvfr
overnight...as southeast and southwest flow should keep cigs/vis
in the mvfr/vfr range. Winds become southwest 5 to 10 knots
with localized gusts 15 to 20 knots possible by midday Thursday.


Outlook...

Thursday Night: Mainly VFR, with local MVFR possible. Slight
chance SHRA.
Friday: VFR. Chance SHRA.
Friday Night: Mainly MVFR, with local IFR possible. Chance SHRA.
Saturday: Mainly VFR, with local MVFR possible. Chance SHRA.
Saturday Night: Mainly VFR, with local IFR possible. Chance SHRA,
Chance SHSN.
Sunday: Mainly MVFR, with areas VFR possible. Chance SHRA.
Sunday Night: Mainly MVFR, with areas VFR possible. Slight chance
SHRA, Slight chance SHSN.
Monday: Mainly VFR, with local MVFR possible. NO SIG WX.

&&

.BTV WATCHES/WARNINGS/ADVISORIES...
VT...None.
NY...None.

&&

$$
SYNOPSIS...JMG
NEAR TERM...JMG/Taber
SHORT TERM...RSD
LONG TERM...RSD
AVIATION...Taber